Name: a novel in vivo gene transfer technique and in vitro cell based assays for the study of bone loss in musculoskeletal disorders
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Description: Watch this Scientific Journal Video about A Novel in vivo Gene Transfer Technique and in vitro Cell Based Assays for the Study of Bone Loss in Musculoskeletal Disorders at JoVE.com

Research was partly supported by NIH research grants R01 AR062173 and SHC 250862 to IEA. ES is the recipient of NIH T32 CTSC predoctoral fellowship.

1. Hydrodynamic Delivery of sRANKL MC DNA
<ol>
	<li>Hydrodynamic Delivery via Mouse Tail Vein
	<ol>
		<li>Weigh the mouse before the tail vein injection. Dilute sRANKL or green fluorescent protein (GFP) MC in Ringer's solution (pre-warm at 37 &#176;C) in a total volume of ~10% of the mouse's body weight.</li>
		<li>Warm up the mouse in a cage for 10 min prior to injection in order to dilate blood vessels and make lateral veins (LVs) visible. Monitor the mouse carefully to avoid dehydration and hyperthermia.</li>
		<li>...

<ol>
	<li>Yelin, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cost+of+musculoskeletal+diseases:+impact+of+work+disability+and+functional+decline.">Cost of musculoskeletal diseases: impact of work disability and functional decline.</a> The Journal of rheumatology. Supplement. 68, 8-11 (2003).</li><li>Boyce, B. F., Rosenberg, E., de Papp, A. E., Duong le, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+osteoclast,+bone+remodelling+and+treatment+of+metabolic+bone+disease.">The osteoclast, bone remodelling and treatment of metabolic bone disease.</a> European journal of clinical investigation. 42, 1332-1341 (2012).</li><li>Lacey, D. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Osteoprotegerin+ligand+is+a+cytokine+that+regulates+osteoclast+differentiation+and+activation.">Osteoprotegerin ligand is a cytokine that regulates osteoclast differentiation and activation.</a> Cell. 93, 165-176 (1998).</li><li>Mizuno, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transgenic+mice+overexpressing+soluble+osteoclast+differentiation+factor+(sODF)+exhibit+severe+osteoporosis.">Transgenic mice overexpressing soluble osteoclast differentiation factor (sODF) exhibit severe osteoporosis.</a> Journal of bone and mineral metabolism. 20, 337-344 (2002).</li><li>Bucay, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=osteoprotegerin-deficient+mice+develop+early+onset+osteoporosis+and+arterial+calcification.">osteoprotegerin-deficient mice develop early onset osteoporosis and arterial calcification.</a> Gene., &amp; development. 12, 1260-1268 (1998).</li><li>Suda, T., Liu, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hydrodynamic+gene+delivery:+its+principles+and+applications.">Hydrodynamic gene delivery: its principles and applications.</a> Molecular therapy: the journal of the American Society of Gene Therapy. 15, 2063-2069 (2007).</li><li>Wronski, T. J., Dann, L. M., Scott, K. S., Cintron, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Long-term+effects+of+ovariectomy+and+aging+on+the+rat+skeleton.">Long-term effects of ovariectomy and aging on the rat skeleton.</a> Calcified tissue international. 45, 360-366 (1989).</li><li>Seto, H., Aoki, K., Kasugai, S., Ohya, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Trabecular+bone+turnover,+bone+marrow+cell+development,+and+gene+expression+of+bone+matrix+proteins+after+low+calcium+feeding+in+rats.">Trabecular bone turnover, bone marrow cell development, and gene expression of bone matrix proteins after low calcium feeding in rats.</a> Bone. 25, 687-695 (1999).</li><li>Lelovas, P. P., Xanthos, T. T., Thoma, S. E., Lyritis, G. P., Dontas, I. 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E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Estrogen+promotes+apoptosis+of+murine+osteoclasts+mediated+by+TGF-beta.">Estrogen promotes apoptosis of murine osteoclasts mediated by TGF-beta.</a> Nature medicine. 2, 1132-1136 (1996).</li><li>Kousteni, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nongenotropic,+sex-nonspecific+signaling+through+the+estrogen+or+androgen+receptors:+dissociation+from+transcriptional+activity.">Nongenotropic, sex-nonspecific signaling through the estrogen or androgen receptors: dissociation from transcriptional activity.</a> Cell. 104, 719-730 (2001).</li><li>Ominsky, M. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=RANKL+inhibition+with+osteoprotegerin+increases+bone+strength+by+improving+cortical+and+trabecular+bone+architecture+in+ovariectomized+rats.">RANKL inhibition with osteoprotegerin increases bone strength by improving cortical and trabecular bone architecture in ovariectomized rats.</a> Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research. 23, 672-682 (2008).</li><li>Kitazawa, R., Kimble, R. B., Vannice, J. L., Kung, V. T., Pacifici, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Interleukin-1+receptor+antagonist+and+tumor+necrosis+factor+binding+protein+decrease+osteoclast+formation+and+bone+resorption+in+ovariectomized+mice.">Interleukin-1 receptor antagonist and tumor necrosis factor binding protein decrease osteoclast formation and bone resorption in ovariectomized mice.</a> The Journal of clinical investigation. 94, 2397-2406 (1994).</li><li>Weitzmann, M. N., Pacifici, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Estrogen+deficiency+and+bone+loss:+an+inflammatory+tale.">Estrogen deficiency and bone loss: an inflammatory tale.</a> The Journal of clinical investigation. 116, 1186-1194 (2006).</li><li>Suda, T., Nakamura, I., Jimi, E., Takahashi, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+of+osteoclast+function.">Regulation of osteoclast function.</a> J Bone Miner Res. 12, 869-879 (1997).</li><li>Asagiri, M., Takayanagi, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+molecular+understanding+of+osteoclast+differentiation.">The molecular understanding of osteoclast differentiation.</a> Bone. 40, 251-264 (2007).</li><li>Matsuzaki, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Osteoclast+differentiation+factor+(ODF)+induces+osteoclast-like+cell+formation+in+human+peripheral+blood+mononuclear+cell+cultures.">Osteoclast differentiation factor (ODF) induces osteoclast-like cell formation in human peripheral blood mononuclear cell cultures.</a> Biochemical and biophysical research communications. 246, 199-204 (1998).</li><li>Adamopoulos, I. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synovial+fluid+macrophages+are+capable+of+osteoclast+formation+and+resorption.">Synovial fluid macrophages are capable of osteoclast formation and resorption.</a> The Journal of pathology. 208, 35-43 (2006).</li><li>Adamopoulos, I. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Interleukin-17A+upregulates+receptor+activator+of+NF-kappaB+on+osteoclast+precursors.">Interleukin-17A upregulates receptor activator of NF-kappaB on osteoclast precursors.</a> Arthritis researc., &amp; therapy. 12, (2010).</li><li>Jones, D., Glimcher, L. H., Aliprantis, A. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Osteoimmunology+at+the+nexus+of+arthritis,+osteoporosis,+cancer,+and+infection.">Osteoimmunology at the nexus of arthritis, osteoporosis, cancer, and infection.</a> J Clin Invest. 121, 2534-2542 (2011).</li><li>Sato, K., Takayanagi, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Osteoclasts,+rheumatoid+arthritis,+and+osteoimmunology.">Osteoclasts, rheumatoid arthritis, and osteoimmunology.</a> Curr Opin Rheumatol. 18, 419-426 (2006).</li><li>Das, S., Crockett, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Osteoporosis+-+a+current+view+of+pharmacological+prevention+and+treatment.">Osteoporosis - a current view of pharmacological prevention and treatment.</a> Drug design, development and therapy. 7, 435-448 (2013).</li><li>Chen, Z. Y., He, C. Y., Ehrhardt, A., Kay, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Minicircle+DNA+vectors+devoid+of+bacterial+DNA+result+in+persistent+and+high-level+transgene+expression+in+vivo.">Minicircle DNA vectors devoid of bacterial DNA result in persistent and high-level transgene expression in vivo.</a> Molecular therapy : the journal of the American Society of Gene Therapy. 8, 495-500 (2003).</li><li>Kay, M. A., He, C. Y., Chen, Z. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+robust+system+for+production+of+minicircle+DNA+vectors.">A robust system for production of minicircle DNA vectors.</a> Nature biotechnology. 28, 1287-1289 (2010).</li><li>Chen, Z. Y., He, C. Y., Kay, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improved+production+and+purification+of+minicircle+DNA+vector+free+of+plasmid+bacterial+sequences+and+capable+of+persistent+transgene+expression+in+vivo.">Improved production and purification of minicircle DNA vector free of plasmid bacterial sequences and capable of persistent transgene expression in vivo.</a> Human gene therapy. 16, 126-131 (2005).</li><li>Halleen, J. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tartrate-resistant+acid+phosphatase+5b:+a+novel+serum+marker+of+bone+resorption.">Tartrate-resistant acid phosphatase 5b: a novel serum marker of bone resorption.</a> Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research. 15, 1337-1345 (2000).</li><li>Adamopoulos, I. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=IL-23+is+critical+for+induction+of+arthritis,+osteoclast+formation,+and+maintenance+of+bone+mass.">IL-23 is critical for induction of arthritis, osteoclast formation, and maintenance of bone mass.</a> J Immunol. 187, 951-959 (2011).</li><li>Suda, T., Takahashi, N., Martin, T. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modulation+of+osteoclast+differentiation.">Modulation of osteoclast differentiation.</a> Endocrine reviews. 13, 66-80 (1992).</li><li>Takahashi, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Osteoblastic+cells+are+involved+in+osteoclast+formation.">Osteoblastic cells are involved in osteoclast formation.</a> Endocrinology. 123, 2600-2602 (1988).</li><li>Bradley, E. W., Oursler, M. 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Musculoskeletal conditions are leading causes of morbidity and disability and are comprised of over 150 diseases and syndromes; affecting approximately 90 million Americans today. Joint inflammation and bone destruction are predominant features of musculoskeletal conditions, including arthritis and osteoporosis. Osteoporosis is a condition that weakens bone integrity, often leading to fractures of the bone. Arthritis is a chronic, debilitating disease characterized by inflammation of the joints that become swollen, tende...

Musculoskeletal diseases affect millions of people in the United States and present severe consequences for national and local health systems1. These disorders are characterized by loss of bone and joint function that require extensive treatment and long periods of recovery. Commonly, a relative increase in the number and/or activity of osteoclasts, cells specialized to resorb bone, in osteoporosis and arthritis is observed2. Under physiological conditions the number and activity of osteoclasts is regulated by receptor activator of nuclear factor &#954;-B ligand (RANKL), which is produced by osteoblasts. Osteoprotegerin (OPG), a decoy receptor for RANKL is also produced by osteoblasts3. In vivo animal models that involve systemic overexpression of sRANKL, or deletion of OPG are very valuable in osteoporosis research; however, these methods require the generation of transgenic mice4,5. Here, a novel alternative method of overexpressing sRANKL for the study of musculoskeletal-related disorders is described. Specifically, minicircle (MC) DNA technology and hydrodynamic delivery methods were used to achieve gene transfer of sRANKL in vivo and overexpress mouse sRANKL systemically6.
This method is also complementary to other in vivo models of osteoporosis, such as hormonal modulation of osteoclasts following ovariectomy7 and dietary intervention by low-calcium diet8. These models are very useful to study different aspects of musculoskeletal-related disorders however they require surgical procedures and may take up to several months, at a significant cost9. Ovariectomized (OVX) rodent model is an experimental animal model where removal of ovaries leads to estrogen deficiency thereby mimicking human postmenopausal osteoporosis10. Human post-menopausal osteoporosis, a condition where estrogen deficiency leads to increased risk of bone fractures and osteoporosis affects approximately eight million women in the United States alone. Although the OVX model is useful for post-menopausal osteoporosis it offers limited advantages in studying osteoporosis in general. Estrogen suppresses bone loss, by inducing osteoclast and inhibiting osteoblast apoptosis, therefore in its absence an increased osteoclast activity is observed10-12. A RANKL-OPG ratio imbalance that favors bone resorption is also observed13. However, estrogen deficiency in vivo is also accompanied by decreased levels of transforming growth factor &#946; (TGF &#946;), increased interleukin-7 (IL-7) and TNF, IL-1 and IL-614,15. As these cytokines have known bone remodeling modulatory functions independent of the RANKL pathway, it is impossible to attribute any osteoclast activation solely to the RANKL-RANK axis. The model described in this paper enables researchers to study in vivo RANKL-RANK axis in osteoclastogenesis and bone loss without pro-inflammatory cytokines compared to OVX rodent models.
Additionally, in vitro osteoclastogenesis techniques are essential tools to study osteoclast activation for potential therapeutic treatments of musculoskeletal diseases. Previous studies have also shown that culturing mouse bone marrow derived macrophages (BMMs) with mouse macrophage colony-stimulating factor (M-CSF) and mouse sRANKL can lead to osteoclast differentiation3,16,17. Here, the protocols to generate multinucleated osteoclast-like cells from mouse bone marrow as well as from human peripheral blood mononuclear cells (PBMCs) in vitro18 are described. The cell-based assays required to define a mature terminally differentiated and fully functional osteoclast are also briefly described. These in vitro techniques complement the novel in vivo approach and together serve as powerful investigative tools to study osteoclast differentiation and activation. Using these systems, scientists are able to generate osteoclasts in vivo and in vitro and define the stimuli and signals required for their proliferation and activation as well as test the efficacy of pharmacological and biological inhibitors.

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	<tbody>
		<tr height="63">
			<td height="63" style="height:63px;width:320px;">alpha-MEM</td>
			<td style="width:71px;">Life Technologies&#160;</td>
			<td style="width:119px;">12561-056</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:320px;">Human M-CSF</td>
			<td style="width:71px;">Miltenyi Biotec</td>
			<td style="width:119px;">130-096-492</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:320px;">Mouse M-CSF</td>
			<td style="width:71px;">Miltenyi Biotec</td>
			<td style="width:119px;">130-094-643</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:320px;">Human RANK-Ligand - soluble</td>
			<td style="width:71px;">Miltenyi Biotec</td>
			<td>130-094-631</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:320px;">Mouse RANK-Ligand - soluble</td>
			<td style="width:71px;">Miltenyi Biotec</td>
			<td style="width:119px;">130-094-076</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:320px;">Tailveiner Restrainer for mice</td>
			<td style="width:71px;">Braintree</td>
			<td style="width:119px;">TV-150 STD</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">Mouse TRANCE/RANK L/TNFSF11 Quantikine ELISA Kit&#160;</td>
			<td style="width:71px;">R&#38;D systems</td>
			<td style="width:119px;">MTR00</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Acid Phosphatase, Leukocyte (TRAP) Kit</td>
			<td style="width:71px;">Sigma</td>
			<td style="width:119px;">387A</td>
			<td></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:320px;">MouseTRAP assay&#160;</td>
			<td style="width:71px;">immunodiagnostic systems</td>
			<td style="width:119px;">SB-TR103</td>
			<td></td>
		</tr>
	</tbody>
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a novel in vivo gene transfer technique and in vitro cell based assays for the study of bone loss in musculoskeletal disorders

Differentiation and activation of osteoclasts play a key role in the development of musculoskeletal diseases as these cells are primarily involved in bone resorption. Osteoclasts can be generated in vitro from monocyte/macrophage precursor cells in the presence of certain cytokines, which promote survival and differentiation. Here, both in vivo and in vitro techniques are demonstrated, which allow scientists to study different cytokine contributions towards osteoclast differentiation, signaling, and activation. The minicircle DNA delivery gene transfer system provides an alternative method to establish an osteoporosis-related model is particularly useful to study the efficacy of various pharmacological inhibitors in vivo. Similarly, in vitro culturing protocols for producing osteoclasts from human precursor cells in the presence of specific cytokines enables scientists to study osteoclastogenesis in human cells for translational applications. Combined, these techniques have the potential to accelerate drug discovery efforts for osteoclast-specific targeted therapeutics, which may benefit millions of osteoporosis and arthritis patients worldwide.

Here, a novel gene transfer technique for differentiation of osteoclasts in vivo and cell culture protocols for differentiating precursor cells into osteoclasts in vitro as a method to study the effects of cytokines on osteoclastogenesis are described. In Figure 1, the representative results of successful gene transfer of GFP and mouse sRANKL MC in mice are shown. In Figure 2, the representative images of mouse bone marrow or human PBMC cell differentiation time course ...

Watch this Scientific Journal Video about A Novel in vivo Gene Transfer Technique and in vitro Cell Based Assays for the Study of Bone Loss in Musculoskeletal Disorders at JoVE.com

A Novel in vivo Gene Transfer Technique and in vitro Cell Based Assays for the Study of Bone Loss in Musculoskeletal Disorders

Differentiation of precursor cells into osteoclasts is regulated by cytokines and growth factors. Here, a novel gene transfer technique for differentiation of osteoclasts in vivo and cell culture protocols for differentiating precursor cells into osteoclasts in vitro as a method to study the effects of cytokines on osteoclastogenesis are described.

A Novel in vivo Gene Transfer Technique and in vitro Cell Based Assays for the Study of Bone Loss in Musculoskeletal Disorders

Differentiation and activation of osteoclasts play a key role in the development of musculoskeletal diseases as these cells are primarily involved in bone ...

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A Strategy to Identify de Novo Mutations in Common Disorders such as Autism and Schizophrenia

There are several lines of evidence supporting the role of de novo mutations as a mechanism for common disorders, such as autism and schizophrenia. First, the de novo mutation rate in humans is relatively high, so new mutations are generated at a high frequency in the population. However, de novo mutations have not been reported in most common diseases. Mutations in genes leading to severe diseases where there is a strong negative selection against the phenotype, such as lethality in embryonic stages or reduced reproductive fitness, will not be transmitted to multiple family members, and therefore will not be detected by linkage gene mapping or association studies. The observation of very high concordance in monozygotic twins and very low concordance in dizygotic twins also strongly supports the hypothesis that a significant fraction of cases may result from new mutations. Such is the case for diseases such as autism and schizophrenia. Second, despite reduced reproductive fitness1 and extremely variable environmental factors, the incidence of some diseases is maintained worldwide at a relatively high and constant rate. This is the case for autism and schizophrenia, with an incidence of approximately 1% worldwide. Mutational load can be thought of as a balance between selection for or against a deleterious mutation and its production by de novo mutation. Lower rates of reproduction constitute a negative selection factor that should reduce the number of mutant alleles in the population, ultimately leading to decreased disease prevalence. These selective pressures tend to be of different intensity in different environments. Nonetheless, these severe mental disorders have been maintained at a constant relatively high prevalence in the worldwide population across a wide range of cultures and countries despite a strong negative selection against them2. This is not what one would predict in diseases with reduced reproductive fitness, unless there was a high new mutation rate. Finally, the effects of paternal age: there is a significantly increased risk of the disease with increasing paternal age, which could result from the age related increase in paternal de novo mutations. This is the case for autism and schizophrenia3. The male-to-female ratio of mutation rate is estimated at about 4&#x2013;6:1, presumably due to a higher number of germ-cell divisions with age in males. Therefore, one would predict that de novo mutations would more frequently come from males, particularly older males4. A high rate of new mutations may in part explain why genetic studies have so far failed to identify many genes predisposing to complexes diseases genes, such as autism and schizophrenia, and why diseases have been identified for a mere 3% of genes in the human genome. Identification for de novo mutations as a cause of a disease requires a targeted molecular approach, which includes studying parents and affected subjects. The process for determining if the genetic basis of a disease may result in part from de novo mutations and the molecular approach to establish this link will be illustrated, using autism and schizophrenia as examples.

Molecular genetic strategy for finding de novo mutations causing common disorders such as autism and schizophrenia.

There are several lines of evidence supporting the role of de novo mutations as a mechanism for common disorders, such as autism and schizophrenia. First, ...

Establishment and Propagation of Human Retinoblastoma Tumors in Immune Deficient Mice

Culturing retinoblastoma tumor cells in defined stem cell media gives rise to primary tumorspheres that can be grown and maintained for only a limited time. These cultured tumorspheres may exhibit markedly different cellular phenotypes when compared to the original tumors. Demonstration that cultured cells have the capability of forming new tumors is important to ensure that cultured cells model the biology of the original tumor. 
Here we present a protocol for propagating human retinoblastoma tumors in vivo using Rag2-/- immune deficient mice. Cultured human retinoblastoma tumorspheres of low passage or cells obtained from freshly harvested human retinoblastoma tumors injected directly into the vitreous cavity of murine eyes form tumors within 2-4 weeks. These tumors can be harvested and either further passaged into murine eyes in vivo or grown as tumorspheres in vitro. Propagation has been successfully carried out for at least three passages thus establishing a continuing source of human retinoblastoma tissue for further experimentation. 
Wesley S. Bond and Lalita Wadhwa are co-first authors.

A method is described to propagate human retinoblastoma tumors in mice. Tumor cells are directly injected into the eyes of immune deficient mice. Secondary tumors have been successfully established using both cells directly harvested from human tumors and cultured tumorspheres.

Culturing retinoblastoma tumor cells in defined stem cell media gives rise to primary tumorspheres that can be grown and maintained for only a limited ...

Longitudinal Evaluation of Mouse Hind Limb Bone Loss After Spinal Cord Injury using Novel, in vivo, Methodology

Spinal cord injury (SCI) is often accompanied by osteoporosis in the sublesional regions of the pelvis and lower extremities, leading to a higher frequency of fractures 1. As these fractures often occur in regions that have lost normal sensory function, the patient is at a greater risk of fracture-dependent pathologies, including death. SCI-dependent loss in both bone mineral density (BMD, grams/cm2) and bone mineral content (BMC, grams) has been attributed to mechanical disuse 2, aberrant neuronal signaling 3 and hormonal changes 4. The use of rodent models of SCI-induced osteoporosis can provide invaluable information regarding the mechanisms underlying the development of osteoporosis following SCI as well as a test environment for the generation of new therapies 5-7 (and reviewed in 8). Mouse models of SCI are of great interest as they permit a reductionist approach to mechanism-based assessment through the use of null and transgenic mice. While such models have provided important data, there is still a need for minimally-invasive, reliable, reproducible, and quantifiable methods in determining the extent of bone loss following SCI, particularly over time and within the same cohort of experimental animals, to improve diagnosis, treatment methods, and/or prevention of SCI-induced osteoporosis.
An ideal method for measuring bone density in rodents would allow multiple, sequential (over time) exposures to low-levels of X-ray radiation. This study describes the use of a new whole-animal scanner, the IVIS Lumina XR (Caliper Instruments) that can be used to provide low-energy (1-3 milligray (mGy)) high-resolution, high-magnification X-ray images of mouse hind limb bones over time following SCI. Significant bone density loss was seen in the tibiae of mice by 10 days post-spinal transection when compared to uninjured, age-matched control (na&iuml;ve) mice (13% decrease, p&lt;0.0005). Loss of bone density in the distal femur was also detectable by day 10 post-SCI, while a loss of density in the proximal femur was not detectable until 40 days post injury (7% decrease, p&lt;0.05). SCI-dependent loss of mouse femur density was confirmed post-mortem through the use of Dual-energy X-ray Absorptiometry (DXA), the current "gold standard" for bone density measurements. We detect a 12% loss of BMC in the femurs of mice at 40 days post-SCI using the IVIS Lumina XR. This compares favorably with a previously reported BMC loss of 13.5% by Picard and colleagues who used DXA analysis on mouse femurs post-mortem 30 days post-SCI 9. Our results suggest that the IVIS Lumina XR provides a novel, high-resolution/high-magnification method for performing long-term, longitudinal measurements of hind limb bone density in the mouse following SCI.

Longitudinal Evaluation of Mouse Hind Limb Bone Loss After Spinal Cord Injury using Novel, in vivo, Methodology

A longitudinal examination of bone loss in the femurs and tibiae of adult mice was performed following spinal cord injury using sequential low-dose X-ray scans. Tibia bone loss was detected throughout the study, while bone loss in the femur was not detected until 40 days post injury.

Spinal cord injury (SCI) is often accompanied by osteoporosis in the sublesional regions of the pelvis and lower extremities, leading to a higher ...

Biomarkers in an Animal Model for Revealing Neural, Hematologic, and Behavioral Correlates of PTSD

Identification of biomarkers representing the evolution of the pathophysiology of Post Traumatic Stress Disorder (PTSD) is vitally important, not only for objective diagnosis but also for the evaluation of therapeutic efficacy and resilience to trauma. Ongoing research is directed at identifying molecular biomarkers for PTSD, including traumatic stress induced proteins, transcriptomes, genomic variances and genetic modulators, using biologic samples from subjects' blood, saliva, urine, and postmortem brain tissues. However, the correlation of these biomarker molecules in peripheral or postmortem samples to altered brain functions associated with psychiatric symptoms in PTSD remains unresolved. Here, we present an animal model of PTSD in which both peripheral blood and central brain biomarkers, as well as behavioral phenotype, can be collected and measured, thus providing the needed correlation of the central biomarkers of PTSD, which are mechanistic and pathognomonic but cannot be collected from people, with the peripheral biomarkers and behavioral phenotypes, which can.
Our animal model of PTSD employs restraint and tail shocks repeated for three continuous days - the inescapable tail-shock model (ITS) in rats. This ITS model mimics the pathophysiology of PTSD 17, 7, 4, 10. We and others have verified that the ITS model induces behavioral and neurobiological alterations similar to those found in PTSD subjects 17, 7, 10, 9. Specifically, these stressed rats exhibit (1) a delayed and exaggerated startle response appearing several days after stressor cessation, which given the compressed time scale of the rat's life compared to a humans, corresponds to the one to three months delay of symptoms in PTSD patients (DSM-IV-TR PTSD Criterian D/E 13), (2) enhanced plasma corticosterone (CORT) for several days, indicating compromise of the hypothalamopituitary axis (HPA), and (3) retarded body weight gain after stressor cessation, indicating dysfunction of metabolic regulation.
The experimental paradigms employed for this model are: (1) a learned helplessness paradigm in the rat assayed by measurement of acoustic startle response (ASR) and a charting of body mass; (2) microdissection of the rat brain into regions and nuclei; (3) enzyme-linked immunosorbent assay (ELISA) for blood levels of CORT; (4) a gene expression microarray plus related bioinformatics tools 18. This microarray, dubbed rMNChip, focuses on mitochondrial and mitochondria-related nuclear genes in the rat so as to specifically address the neuronal bioenergetics hypothesized to be involved in PTSD.

We describe a rat model of post traumatic stress disorder (PTSD) that reveals the persistent alterations in neuroendocrine function and the delayed long-term, exaggerated fear response, characteristic of PTSD patients. The animal model and methods described here are useful for correlating biomarkers in brain nuclei, which are mechanistic but cannot be measured in patients, with biomarkers in peripheral white blood cells, which can.

Identification of biomarkers representing the evolution of the pathophysiology of Post Traumatic Stress Disorder (PTSD) is vitally important, not only for ...

A Novel Surgical Approach for Intratracheal Administration of Bioactive Agents in a Fetal Mouse Model

Prenatal pulmonary delivery of cells, genes or pharmacologic agents could provide the basis for new therapeutic strategies for a variety of genetic and acquired diseases. Apart from congenital or inherited abnormalities with the requirement for long-term expression of the delivered gene, several non-inherited perinatal conditions, where short-term gene expression or pharmacological intervention is sufficient to achieve therapeutic effects, are considered as potential future indications for this kind of approach. Candidate diseases for the application of short-term prenatal therapy could be the transient neonatal deficiency of surfactant protein B causing neonatal respiratory distress syndrome1,2 or hyperoxic injuries of the neonatal lung3. Candidate diseases for permanent therapeutic correction are Cystic Fibrosis (CF)4, genetic variants of surfactant deficiencies5 and &alpha;1-antitrypsin deficiency6.
Generally, an important advantage of prenatal gene therapy is the ability to start therapeutic intervention early in development, at or even prior to clinical manifestations in the patient, thus preventing irreparable damage to the individual. In addition, fetal organs have an increased cell proliferation rate as compared to adult organs, which could allow a more efficient gene or stem cell transfer into the fetus. Furthermore, in utero gene delivery is performed when the individual's immune system is not completely mature. Therefore, transplantation of heterologous cells or supplementation of a non-functional or absent protein with a correct version should not cause immune sensitization to the cell, vector or transgene product, which has recently been proven to be the case with both cellular and genetic therapies7.
In the present study, we investigated the potential to directly target the fetal trachea in a mouse model. This procedure is in use in larger animal models such as rabbits and sheep8, and even in a clinical setting9, but has to date not been performed before in a mouse model. When studying the potential of fetal gene therapy for genetic diseases such as CF, the mouse model is very useful as a first proof-of-concept because of the wide availability of different transgenic mouse strains, the well documented embryogenesis and fetal development, less stringent ethical regulations, short gestation and the large litter size.
Different access routes have been described to target the fetal rodent lung, including intra-amniotic injection10-12, (ultrasound-guided) intrapulmonary injection13,14 and intravenous administration into the yolk sac vessels15,16 or umbilical vein17. Our novel surgical procedure enables researchers to inject the agent of choice directly into the fetal mouse trachea which allows for a more efficient delivery to the airways than existing techniques18.

We developed a novel surgical approach for intratracheal administration of bioactive agents into the mouse fetus. The delivery route is more efficient in targeting the fetal mouse lungs than the commonly used intra-amniotic injection. This procedure has to date not been described in a mouse model.

Prenatal pulmonary delivery of cells, genes or pharmacologic agents could provide the basis for new therapeutic strategies for a variety of genetic and ...

Development of an Audio-based Virtual Gaming Environment to Assist with Navigation Skills in the Blind

Audio-based Environment Simulator (AbES) is virtual environment software designed to improve real world navigation skills in the blind. Using only audio based cues and set within the context of a video game metaphor, users gather relevant spatial information regarding a building's layout. This allows the user to develop an accurate spatial cognitive map of a large-scale three-dimensional space that can be manipulated for the purposes of a real indoor navigation task. After game play, participants are then assessed on their ability to navigate within the target physical building represented in the game. Preliminary results suggest that early blind users were able to acquire relevant information regarding the spatial layout of a previously unfamiliar building as indexed by their performance on a series of navigation tasks. These tasks included path finding through the virtual and physical building, as well as a series of drop off tasks. We find that the immersive and highly interactive nature of the AbES software appears to greatly engage the blind user to actively explore the virtual environment. Applications of this approach may extend to larger populations of visually impaired individuals.

Audio-based Environment Simulator (AbES) is virtual environment software designed to improve real world navigation skills in the blind.

Audio-based Environment Simulator (AbES) is virtual environment software designed to improve real world navigation skills in the blind. Using only audio ...

A Novel High-resolution In vivo Imaging Technique to Study the Dynamic Response of Intracranial Structures to Tumor Growth and Therapeutics

We have successfully integrated previously established Intracranial window (ICW) technology 1-4 with intravital 2-photon confocal microscopy to develop a novel platform that allows for direct long-term visualization of tissue structure changes intracranially. Imaging at a single cell resolution in a real-time fashion provides supplementary dynamic information beyond that provided by standard end-point histological analysis, which looks solely at 'snap-shot' cross sections of tissue.
Establishing this intravital imaging technique in fluorescent chimeric mice, we are able to image four fluorescent channels simultaneously. By incorporating fluorescently labeled cells, such as GFP+ bone marrow, it is possible to track the fate of these cells studying their long-term migration, integration and differentiation within tissue. Further integration of a secondary reporter cell, such as an mCherry glioma tumor line, allows for characterization of cell:cell interactions. Structural changes in the tissue microenvironment can be highlighted through the addition of intra-vital dyes and antibodies, for example CD31 tagged antibodies and Dextran molecules.
Moreover, we describe the combination of our ICW imaging model with a small animal micro-irradiator that provides stereotactic irradiation, creating a platform through which the dynamic tissue changes that occur following the administration of ionizing irradiation can be assessed.
Current limitations of our model include penetrance of the microscope, which is limited to a depth of up to 900 &mu;m from the sub cortical surface, limiting imaging to the dorsal axis of the brain. The presence of the skull bone makes the ICW a more challenging technical procedure, compared to the more established and utilized chamber models currently used to study mammary tissue and fat pads 5-7. In addition, the ICW provides many challenges when optimizing the imaging.

A Novel High-resolution In vivo Imaging Technique to Study the Dynamic Response of Intracranial Structures to Tumor Growth and Therapeutics

We describe a novel in vivo imaging technique that couples fluorescent chimeric mice with intracranial windows and high-resolution 2-photon microscopy. This imaging platform aids studies of dynamic changes in brain tissue and microvasculature, at a single-cell level, following pathological insults and is adaptable to assess intracranial drug delivery and distribution.

We have successfully integrated previously established Intracranial window (ICW) technology 1-4 with intravital 2-photon confocal microscopy to develop a ...

Cell-based Assay Protocol for the Prognostic Prediction of Idiopathic Scoliosis Using Cellular Dielectric Spectroscopy

This protocol details the experimental and analytical procedure for a cell-based assay developed in our laboratory as a functional test to predict the prognosis of idiopathic scoliosis in asymptomatic and affected children. The assay consists of the evaluation of the functional status of Gi and Gs proteins in peripheral blood mononuclear cells (PBMCs) by cellular dielectric spectroscopy (CDS), using an automated CDS-based instrument, and the classification of children into three functional groups (FG1, FG2, FG3) with respect to the profile of imbalance between the degree of response to Gi and Gs proteins stimulation. The classification is further confirmed by the differential effect of osteopontin (OPN) on response to Gi stimulation among groups and the severe progression of disease is referenced by FG2. Approximately, a volume of 10 ml of blood is required to extract PBMCs by Ficoll-gradient and cells are then stored in liquid nitrogen. The adequate number of PBMCs to perform the assay is obtained after two days of cell culture. Essentially, cells are first incubated with phytohemmaglutinin (PHA). After 24 hr incubation, medium is replaced by a PHA-free culture medium for an additional 24 hr prior to cell seeding and OPN treatment. Cells are then spectroscopically screened for their responses to somatostatin and isoproterenol, which respectively activate Gi and Gs proteins through their cognate receptors. Both somatostatin and isoproterenol are simultaneously injected with an integrated fluidics system and the cells&#39; responses are monitored for 15 min. The assay can be performed with fresh or frozen PBMCs and the procedure is completed within 4 days.

A structured protocol is presented for a cell-based assay as a functional test to predict the prognosis of idiopathic scoliosis using cellular dielectric spectroscopy (CDS). The assay can be performed with fresh or frozen peripheral blood mononuclear cells (PBMCs) and the procedure is completed within 4 days.

This protocol details the experimental and analytical procedure for a cell-based assay developed in our laboratory as a functional test to predict the ...

In vivo 19F MRI for Cell Tracking

In vivo 19F MRI allows quantitative cell tracking without the use of ionizing radiation. It is a noninvasive technique that can be applied to humans. Here, we describe a general protocol for cell labeling, imaging, and image processing. The technique is applicable to various cell types and animal models, although here we focus on a typical mouse model for tracking murine immune cells. The most important issues for cell labeling are described, as these are relevant to all models. Similarly, key imaging parameters are listed, although the details will vary depending on the MRI system and the individual setup. Finally, we include an image processing protocol for quantification. Variations for this, and other parts of the protocol, are assessed in the Discussion section. Based on the detailed procedure described here, the user will need to adapt the protocol for each specific cell type, cell label, animal model, and imaging setup. Note that the protocol can also be adapted for human use, as long as clinical restrictions are met.

In vivo 19F MRI for Cell Tracking

We describe a general protocol for in vivo cell tracking using MRI in a mouse model with ex vivo labeled cells. A typical protocol for cell labeling, image acquisition processing and quantification is included.

In vivo 19F MRI allows quantitative cell tracking without the use of ionizing radiation. It is a noninvasive technique that can be applied to humans. ...

Carotid Artery Infusions for Pharmacokinetic and Pharmacodynamic Analysis of Taxanes in Mice

When proposing the use of a drug, drug combination, or drug delivery into a novel system, one must assess the pharmacokinetics of the drug in the study model. As the use of mouse models are often a vital step in preclinical drug discovery and drug development1-8, it is necessary to design a system to introduce drugs into mice in a uniform, reproducible manner. Ideally, the system should permit the collection of blood samples at regular intervals over a set time course. The ability to measure drug concentrations by mass-spectrometry, has allowed investigators to follow the changes in plasma drug levels over time in individual mice1, 9, 10. In this study, paclitaxel was introduced into transgenic mice as a continuous arterial infusion over three hours, while blood samples were simultaneously taken by retro-orbital bleeds at set time points. Carotid artery infusions are a potential alternative to jugular vein infusions, when factors such as mammary tumors or other obstructions make jugular infusions impractical. Using this technique, paclitaxel concentrations in plasma and tissue achieved similar levels as compared to jugular infusion. In this tutorial, we will demonstrate how to successfully catheterize the carotid artery by preparing an optimized catheter for the individual mouse model, then show how to insert and secure the catheter into the mouse carotid artery, thread the end of the catheter out through the back of the mouse&#8217;s neck, and hook the mouse to a pump to deliver a controlled rate of drug influx. Multiple low volume retro-orbital bleeds allow for analysis of plasma drug concentrations over time.

This method was developed with the goal of delivering a steady drug solution via the carotid artery, to assess the pharmacokinetics of novel drugs in mouse models.

When proposing the use of a drug, drug combination, or drug delivery into a novel system, one must assess the pharmacokinetics of the drug in the study ...